Graphic-meter-control mechanism



c. AALBoRG GRAPHIC METER CONTROL MECHANISM Filed Sept'` 2. 1922 f Feb.' 16,1926.

Patented Feb. 1), 1926.

i wir :Het 'www1 UNH E@ lfis i i CHRSTAN AALBORG, OF ENNSLTJ L -l c TO VESTING" HOUSE ELECTPEC @t TvIANFACTJn-N CMPLET'Y, fi. GOC fr MINSYL- VANA.

,implication filed Se 5 glieny and State Vof Pennsylvanie, here invented a new and uset'ul mprovennnt in G 'aphic-lvleter-Control Mechanisms, et which the 'following is a specification.

My invention relates to electrical n'ieznsuring` instruments and particularly to m ans for controlling` the movement of the pen or stylus of' a recording inst ent.

@ne object of my invention is to provide a device oi the above-indicated character tnet shall be more sccurntely responsive to actuating impulses over the entire range of its indicating movement.

Another object of my invention is to provide means to so compensate for relative angular movement betweei the movnm member of a Kelvin balance and a rect Y i early movable pen or stylus as to oppose movement of the balance in proportion to movement of the pen.

ln co-pendingg applications of l? Pierce, Serial Nos. 574,259, 574,260 574,261, tiled duly 11, 1922, electrical measuring` instruments, and assigned to the Vilestinghouse Electric et ltanuiecturing Company, to which reference may be had 'to assist in understanding this invention, are set forth other structures operative in accordance with the broad principle et' compensating for the angular relative movement between a Kelvin balance end a recording pen.

lt has heretofore been usual, in recording` instruments of the relay type embodying' a Kelvin balance and e rectilinearly movable stylus carriage, as shown in ntent No. 1,289,503, electrical measuring; instrument, issued Dec. 81, 1918, to l?. MacGahan, to provide a spring, connected. between the balance and the carriage, to oppose more ment of the balance in accordance with movement of the stylus. This construction caused inaccuracies in the operation of the instrument by reason ot the differences in amount of movement between the balance and the stylus. ln other words, by reason ot the difference in the increments of engular movement orn the balance about its pivot relative to the increments ot rectilinear movement of the stylus, the spring was not biased uniformly or in strict prever-tion to movement oi the stylus over the entire rence of n'ioveinent oit the letter.

r v invention is improvement on l lileci; han device, above reterrcd to, in tha certain errors, one of whicn occurs accordance with the sine ot' the angie of deflection of e pivot-ed cum member therein and another of which may be caused by frictional weer of the cam surface, are substantially eliniinered.

"l my ',ivention, l provide two that are so pivoted udjacent to the ot the Kelvin bslsnce and connected 'heir outer ends to the pen carriage ot the insti-iA to uniformly oppose f int et 4ie belance in accordance with movement ot the pen ce1-ringe.

Figure 1 ot the accon'n)enyingv drawings is a view of a portion ot a measuring iustrument embodying my invention, and Eig. 2 is a view ta :en at right ingles to a portion ot 1.

Stationary coils 2 oit a may be suitably supported on a bracket i3, constituting` a portion of 'the instrument frame, which carries a vertical standard The latter supports a pivot lelvin balance or bracket et. pin 5, upon which is mounted the movable member 6 of the llelvin ce, und a pin 7 to which is pivoted depending arm 8.

traveling' nut member 9, constituting supporting` means or cari-'age for a pen or .stylus 22, is mounted on e screw shat 10 that is supported in beerin bracket members 11.

The arm 8 comprises upper und lower sections 12 and 18, respectively, that nre insulated from each other by a body of insulation lilnnd connected by scr-e or rivets 15. i radial slot 1G is provided at an intermediate portion ci? the arm 8 for the reception of e pin 17 at the outer end of an arm 18, that is mounted to turn freely on the pin 5. fr spiral spring` 19 is connected, at its inner end, to the arm 18 and, at its outer end, to the member 6. A. vertical slot 2O in the nut 9 is edapted to receive a pin 21 carried by the lower end ot the arm 8.

The screw shaft 10 is adopted to be rotated by a pilot motor that is controlled by the member 6 through usual contact members 2d. Accordingly, when the Kelvin balance is energized in accordance with a quantity to be measured, the nut 9 Will be moved in proportion to the value of that quantity.

In operation, when the nut 9 advances along the shalt 10, the pins 17 and 2l are so moved in the slots 16 and 20, respectively, as to cause the arm 8 to move the arm 18 by substantially uniform amounts in accordance with the movement of the nut 9. Hence, the spring 19 is Wound and unwound, by substantially uniform amounts, in proportion to movements ot the nut 9, and the member G is constantly opposed by a force equal to the actuating torce thereof.

By my invention, a recording instrument, oi the type described, is obtained which is delicately and accurately responsive to 'the quantity being measured, throughout the range of the instrument.

"While I have shown and described a particular 'form of my invention, changes may be ellected therein without departing from the spirit and scope thereof', as 'set forth in the appended claims.

I claim as my invention l. In a measuring instrument, the combi nation with. a rectilinearly movable indicating member and a pivoted control member thereior, ot an arm pivot-ed to move indepeni'lently about the pivot axis of the control meml er, means for opposing movement ot the control member and a second arm havino a stationary pivot axis and yieldably connected to said l'irst arm and to the ind icating member.

2. In a measuring instrument, the combination with a rectilinearl:vv movable indicating member and a pivoted control member therefor, of an arm pivoted to move independently about the pivot axis ot the control nember, a second arm having a stationary pivot axis and yieldably connected to said first arm and to the indicating member, and means disposed between the lirst arm and the control member and responsive to movement oi the indicating member l'or opposing movement ot the control member.

3. In a measuring` instrument, the combination with a rectilinearly movable indieating` member and a pivoted control inember therefor, ol an arm pivoted to move about the pivot axis of the control member, a spring connected between the control member and the arm, and a second arm having a stationary pivot axis offset With respect to the pivot axis ot the said lirst arm and a lost-motion connection to said first arm and to the indicating member.

bination with a horizontally movable indi' 'ating member and a Kelvin balance disposed thereabove for contrclling` the movement thereof, of an arm pivoted above the pivot o' the balance, lost-motion connecting means between the arm and the indicating member, a second arm movable about the 's of the balaniife, lost-motion connecting means between said arms, and a spring conarm and the ini- 1; member having a vertical slot 'therein and a Kelvin balance disposed thereabove tor controlling the moven'icnt thereof, oi an arm pivoted above the pivot ot the balance, a pin larried by the arm land movable .in .sai-:l slot, a second arm movable about the axis of the balance, a pin-and-slot connection between said arms, and a helical spring coiled about the pivot axis ot the balance and connected between the second arm and the balance.

7. In a measuring instrument, the combination with a. horizontal screw shalt adapted for co-operation with means :for rotating the same, a traveling-nut indicating member disposed on the shaft and having a. vertical slot, and a Kelvin balance disposed above the shatt for controlling said rotating means, of an arm havino apivot axis vertically above the pivot oi" the balance, a pin carried by the lower end ot the arm and extending into said slot, a second arm 'lreely movable about the axis ot the balance, a pin-and-slot connection between the outer end of the second arm and an intermediate portion orc the lirst arm, and a helical spring coiled about the pivot axis ot the balance and connected, at its ends, between the second arm and the balance.

In testimony whereof, I have hereunto subscribed my name this 31st day ot August,

CHRISTIAN AALBORG. 

